If your Vitamin D3 level is very low, it usually means you have Vitamin D Deficiency and you may need treatment to restore normal levels. Doctors commonly recommend vitamin D3 supplements (either daily or weekly high-dose medicines) along with adequate calcium intake if required. Regular sunlight exposure for about 15-20 minutes in the morning, especially on arms and face, can help the body produce vitamin D naturally. Including foods rich in vitamin D such as eggs, fatty fish, fortified milk, and dairy products may also help.

A very low vitamin D level (6.5 ng/mL) can cause bone pain, muscle weakness, and joint discomfort. In your father's case, the swelling and pain in the knee and ankle may be due to a combination of severe Vitamin D Deficiency and age-related joint wear (degenerative changes), which is often related to Osteoarthritis. Treatment usually includes vitamin D supplementation (often high-dose vitamin D for a few weeks, followed by maintenance doses), calcium if needed, pain-relief medicines, and gentle physiotherapy or exercises to strengthen the joints. Sunlight exposure and a balanced diet also help improve vitamin D levels. If swelling persists, it is best to follow up with the doctor to rule out other causes and adjust treatment accordingly.

Rickets is usually caused by vitamin D and calcium deficiency, which can lead to bone pain and difficulty walking. The medicines your doctor prescribed, Shelcal (calcium supplement) and D3 60K (vitamin D), are commonly used to treat this condition. With proper treatment, a balanced diet rich in calcium, adequate sunlight exposure, and regular follow-ups, most children improve well and can recover completely. The pain in the knees and ankles should gradually reduce as the bones become stronger, but it is important to continue the treatment as advised by the doctor.